Struct Relation 

pub struct Relation {
    pub entries: Vec<RelationEntry>,
    pub tables: Vec<String>,
    pub table_column_counts: Vec<usize>,
}

A relation is a collection of entries with table context.

Fields

entries: Vec<RelationEntry>

The entries in this relation.

tables: Vec<String>

Table names in this relation.

table_column_counts: Vec<usize>

Column counts for each table (used for computing offsets in joined relations). The i-th element is the number of columns in the i-th table.

Implementations

impl Relation

pub fn new(tables: Vec<String>) -> Self

Creates a new empty relation.

pub fn new_with_column_counts( tables: Vec<String>, column_counts: Vec<usize>, ) -> Self

Creates a new empty relation with column counts.

pub fn empty() -> Self

Creates an empty relation.

pub fn from_rows(rows: Vec<Rc<Row>>, tables: Vec<String>) -> Self

Creates a relation from Rcs. Uses shared tables to avoid cloning for each row.

pub fn from_rows_with_column_count( rows: Vec<Rc<Row>>, tables: Vec<String>, column_count: usize, ) -> Self

Creates a relation from Rcs with explicit column count.

pub fn from_rows_owned(rows: Vec<Row>, tables: Vec<String>) -> Self

Creates a relation from owned Rows. Uses shared tables to avoid cloning for each row.

pub fn tables(&self) -> &[String]

Returns the tables in this relation.

pub fn table_column_counts(&self) -> &[usize]

Returns the column counts for each table.

pub fn get_table_offset(&self, table_name: &str) -> Option<usize>

Computes the column offset for a given table name. Returns None if the table is not found.

pub fn len(&self) -> usize

Returns the number of entries.

pub fn is_empty(&self) -> bool

Returns true if the relation is empty.

pub fn push(&mut self, entry: RelationEntry)

Adds an entry to the relation.

pub fn iter(&self) -> impl Iterator<Item = &RelationEntry>

Returns an iterator over the entries.

Trait Implementations

impl Clone for Relation

fn clone(&self) -> Relation

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for Relation

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl IntoIterator for Relation

type Item = RelationEntry

The type of the elements being iterated over.

type IntoIter = IntoIter<RelationEntry>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.